1. Field of the Invention
The present invention relates to a high density electrical connector, and particularly to a high density electrical connector having improved grounding buses for reducing electrical crosstalk between signal terminals.
2. Description of Related Art
With the development of communication and computer technology, high density electrical connectors with conductive elements in a matrix arrangement are desired to thereby construct a large number of signal transmitting paths between two electronic devices. Such high density electrical connectors are widely used in internal connecting systems of severs, routers and the like devices requiring high speed data processing and communication. These connectors can be referred to Berg Product Catalog published on January 1998, entitled xe2x80x9cPCB-mounted receptacle assembliesxe2x80x9d, which is submitted herewith by Information Disclosure Statement (IDS), and the website of Teradyne, Inc, at the following internet address: http://www.teradyne.com/prods/tcs/products/hpi/vhdm/modoconfig.html. U.S. Pat. Nos. 6,267,604, 5,980,321, 6,293,827 and 6,299,484 also disclose such high density electrical connectors.
Because the signal transmission speed of these high density electrical connectors is very fast, crosstalk between signal transmitting paths becomes a serious problem. U.S. Pat. No. 6,338,635, issued to Wei-Chen Lee and assigned to Hon Hai Precision Ind. Co., Ltd., discloses an electrical connector that adopts a grounding bus for promoting high quality signal transmission therethrough. The electrical connector comprises an insulative housing defining a cavity in a top face thereof and a plurality of passageways in a bottom face thereof communicating with the cavity, and a plurality of terminals and modules retained in the housing. Each module includes an insulative body and a grounding member attached on a first side of the body. In assembly, the modules are first downwardly inserted into the cavity of the housing, and the terminals are then upwardly inserted into the passageways of the housing to be positioned in an opposite second side of the body of the module. The grounding member forms a plurality of projections extending into the body toward the second side for preventing crosstalk between adjacent terminals of a common row. However, assembling the terminals and the modules into the housing is complicated. In addition, the terminals inserted into the housing must be accurately positioned in the second side of the body of the module, thereby increasing difficulty of assemblage. Thus, the manufacturing cost of the connector is correspondingly increased.
U.S. Pat. No. 6,152,747, issued to Teradyne, Inc., discloses a high density electrical connector comprising a dielectric housing defining a plurality of parallel slots therein and a plurality of wafer-like modules retained in respective slots. Each wafer-like module includes a dielectric support and a plurality of signal contacts and a grounding plate attached at opposite sides of the dielectric support, respectively. Mounting portions of the signal contacts and the grounding plate of the wafer-like module are arranged in a staggered manner for connecting to a printed circuit board on which the connector is mounted. Obviously, the grounding plates function as shielding for reducing crosstalk between adjacent rows of the signal contacts. However, there is no shielding between the mounting portions of the signal contacts of the adjacent rows, so crosstalk between the adjacent rows of the signal contacts is not effectively reduced, thereby adversely affecting signal transmission performance of the connector. U.S. Pat. No. 6,174,202 also discloses some approach.
Hence, an electrical connector with improved grounding bus is required to overcome the disadvantages of the related art.
Accordingly, a first object of the present invention is to provide a high density electrical connector having improved grounding buses for effectively preventing crosstalk between adjacent rows of signal contacts.
A second object of the present invention is to provide a high density electrical connector having grounding buses disposed between adjacent rows of signal contacts, each grounding bus having a plurality of flaps for ensuring better signal transmission performance of the connector.
In order to achieve the objects set forth, a high density electrical connector in accordance with the present invention comprises a plurality of individual wafers assembled together to define slots therebetween for receiving a plurality of circuit boards in the slots. Each wafer includes a dielectric base and a plurality of signal contacts and a grounding bus respectively mounted on opposite sides of the dielectric base. Each grounding bus forms a plurality of flaps adjacent to a bottom edge thereof. Each signal contact has a tail portion adapted for electrically contacting with a printed circuit board on which the electrical connector is mounted, and an end portion located near the tail portion thereof and aligned with a corresponding flap of the grounding bus. The flaps are disposed between the end portions of the signal contacts of adjacent rows for functioning as shielding between the end portions, thereby ensuring better signal transmission performance of the connector.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
FIG. 1 is a perspective view of an electrical connector and a daughter card on which the connector is mounted in accordance with the present invention;
FIG. 2 is a view similar to FIG. 1 but taken from a different perspective;
FIG. 3 is a partially exploded view of the connector of the present invention;
FIG. 4 is a view similar to FIG. 3 but taken from a different perspective;
FIG. 5 is an exploded view of the connector of the present invention and a complementary connector;
FIG. 6 is a perspective view showing the connector of the present invention and the complementary connector in a mated condition;
FIG. 7 is an enlarged perspective view of a wafer of the connector of the present invention;
FIG. 8 is a view similar to FIG. 7 but taken from a different perspective;
FIG. 9 is a perspective view showing a number of the wafer of FIG. 7 assembled together;
FIG. 10 is a cross-sectional view taken along section line 10xe2x80x9410 of FIG. 9 with the assembled wafers mounted on the daughter card;
FIG. 11 is a view similar to FIG. 10 but taken along section line 11xe2x80x9411 of FIG. 9; and
FIG. 12 is a view similar to FIG. 10 with circuit boards being inserted into the assembled wafers.